In recent years, television receivers having playback functions have been put to practical use. Generally, a playback function is implemented by an image memory in a television receiver, and a portion of a program currently being broadcasted is recorded in the memory as a moving picture according to instructions from a user (viewer) who is watching the program, so that the user can reproduce the past broadcast signals retroactively at any time.
Using a television receiver with such a playback function, the user can immediately record any commercial, quiz program, or cooking program, so this function is very effective to utilize the broadcasting information. Meanwhile, another television receiver has a function to display a plurality of programs on a screen at the same time.
Since random access memory (RAM) means capable of mass storage recording in required as a recording medium of a recording and reproduction device included in a television receiver with a playback function, an ordinary semiconductor memory is not suitable because of its high bit price that results in high cost. Hence, it is thought that a hard disk drive unit, which can be regarded as a kind of RAM means, is employed. However, a conventional hard disk drive unit for data processing is usually provided with a single head for both recording and reproduction (hereinafter, referred to as recording/reproduction head) for a single recording surface.
In a recording and reproduction device having a playback function implemented by a conventional hard disk drive unit, when the user watches a program during the actual time without using the playback function, the recording/reproduction head of the hard disk drive unit is used simply for recording the broadcasting signal, so that it performs an ordinary recording operation. The ordinary recording operation is, for a one-side recording hard disk drive unit, to successively record signals on tracks while moving the recording/reproduction head from the outer circumference of the hard disk toward the inner circumference of the hard disk.
On the other hand, when the user uses the playback function while watching a program during the actual time, the recording/reproduction head repeats, alternatingly, the broadcasting signal recording operation and the reproducing operation for playback in a short period of time.
As described above, the conventional recording and reproduction device realizes the playback function by alternatingly repeating the recording and the reproduction using a single recording/reproduction head.
However, when the recording and reproduction device with the playback function is implemented by a conventional hard disk drive unit as mentioned above, since the recording and the reproduction are alternatingly repeated using a single head for recording and reproduction, noise is easily generated, and the lifetime of a head driving system is reduced because of the frequent repetition.
Further, in the recording and reproduction device with the playback function, data is recorded successively on adjacent tracks, from a track on the outermost circumference toward a track on the innermost circumference. Hence, when the recording of data on the innermost track is completed, the head must jump over plural tracks to return to the outermost track for the next recording. This results in an undesired phenomenon that frames of data to be recorded are skipped (hereinafter referred to as frame skip). In addition, when the traveling distance of the head is long, for example, when it travels from the track on the innermost circumference to the track on the outermost circumference, since the head cannot record frames which are generated during the travel of the head, more frames are skipped.
Furthermore, in the recording operation of the conventional head, as mentioned above, the head records data on tracks successively while moving from the outer circumference toward the inner circumference. So, when the recording of data on the track on the innermost circumference is completed, the head must return to the track on the outermost circumference for the next recording operation. This movement of the head seems wasteful.
Furthermore, the conventional television receiver having the playback function can only reproduce the past broadcasting signals, retroactively, for a prescribe period of time from the present time. Therefore, the availability of the playback function by the user is limited to a short period, a single time, and a single channel. Further, when an image in which a part of a program is recorded is reproduced, if the image is displayed on the whole screen, it is not possible to watch a program being broadcasted during the reproduction.
For example, when a user who is watching a sports program A wants to watch a program B which will be broadcasted on another channel from the scheduled ending time of the sports program A, if the sports program A is extended, the user records the program B as a program on another channel. In this case, however, when the user turns the channel to the program B after the program A has been through, he/she watches the program B from the middle and, thereafter, watches the recorded program B from the beginning.
When the program B is a drama, since the user sees the ending of the drama before the beginning, he/she may lose interest in the drama. Alternatively, the user may record the extended part of the sports program A after the scheduled ending time and watches the extended part after the program B has ended. In this case, however, the user will feel uneasy about the progress of the sports program A. As a result, the user must give up watching either of the programs A and B throughout.